Field of the Invention
The present invention relates to a steered wheel suspension device. For example, the present invention is preferable to be employed for a steered wheel suspension device of a small vehicle such as a motorcycle.
Description of the Related Art
A small vehicle such as a motorcycle employs a steered wheel suspension device to suspend a front wheel as a steered wheel. Such small vehicle turns by largely inclining the vehicle (what is called, by banking). At this time, the front wheel sometimes receives a load in a vehicle-width direction. Then, the steered wheel suspension device is required to absorb the load.
Patent document 1 discloses a front wheel support device for a motorcycle that includes an upper bracket and a lower bracket. The upper bracket and lower bracket includes a cut-out portion that is cut from a rear edge toward the front of the vehicle, and a bottomed or a through lightening portion along a front-rear direction. According to the upper bracket and the lower bracket disclosed in Patent Document 1, the rigidity of the bracket is decreased and the behavior of the vehicle is made gentle when the front wheel receives the load in the vehicle-width direction.
Patent Document 1: Japanese Laid-open Patent Publication No. 2008-285050
However, a fork bracket such as the upper bracket and the lower bracket usually requires the strength and the rigidity to some extent since the fork bracket receives the load when the vehicle is decelerated. On the other hand, as described above, the rigidity is required to be decreased to absorb the load that is received by the fork bracket from a steered wheel while inclining the vehicle. That is, the conflicting requirements are posed on the fork bracket.
Here, in the case where the cut-out portion and similar portion is disposed as Patent Document 1 for example, the cut-out portion is required to have a configuration and a peripheral shape that ensure the strength with respect to a stress concentration applied to the cut-out portion. As a result, this makes the shape of the bracket complicated.